# nLab Strøm's theorem

###### Strøm’s theorem

Let $(X,A)$ and $(Y,B)$ be NDR-pairs. Their product in the category of topological pairs

$(X\times Y,X\times B\cup A\times Y)$

is also an NDR-pair.

Last revised on December 3, 2009 at 23:12:57. See the history of this page for a list of all contributions to it.